1. Field of the Invention
The invention regards a degermination procedure.
2. Description of the Related Art
In particular liquid, at least flow capable media, e.g. water and waste water often are germ infested, thus contaminated with living microorganisms like viruses or bacteria, which have to be removed or at least deactivated.
In a typical degermination situation bacteria are in drinking water or in useable water.
The purification was done so far in various ways, depending on the application and the prevailing conditions:
Chemical killing of the microbes is often performed through adding chemical substances destroying the living microorganisms, e.g. chlorine or ozone in a sufficiently strong concentration.
Thereby one of the problems is, that though the mixing never is complete or 100%, it has to be assured, that at any location in the media a sufficient minimum concentration of the added chemical is present, which often means, that such a high concentration is provided in other locations, thereby causing detrimental effects for the user.
Another customary possibility is the removal of the microorganisms from the medium through a cold procedure, e.g. through filtration. The disadvantage is that such fine filters require a very high manufacturing and maintenance effort, since they clog very quickly without sufficient maintenance and, thereby, become impermeable and unusable.
Another possibility is killing the living microorganisms through heat and/or pressure, however, a very high energy consumption occurs. On the other hand, depending on the medium, through the necessary high temperature or pressure, desired chemical, physical or taste properties of the medium are influenced in a detrimental manner.
On the other hand, the cavitation effect is known and is based on the fact that gas bubbles are created in a rapidly flowing liquid and imploded subsequently. During hydrodynamic cavitation, this occurs through high regional pressure differentials in the flowing liquid, mostly caused through strong variations in the flow velocity due to cross section contractions or expansions.
Also known are ultrasonic cavitation and cavitation through local addition of energy, e.g. through a laser beam.
The generation of hydrodynamic cavitation bubbles occurs in a moving liquid through a drop in static pressure below the vapor pressure of the liquid, forming vapor filled gas bubbles, e.g. due to a flow contraction. Subsequently, when the static pressure increases, again through an expansion of the flow cross section and the static pressure increases again above the vapor pressure, the gas bubbles collapse.
The static pressure becomes zero or negative in water when the flow velocity increases beyond a certain value, depending on the environmental conditions, e.g. at the separation edges approximately 14 m/sec.
The contraction and subsequent expansion of the flow cross section can be accomplished by locating an obstacle body in a flow chamber, wherein the remaining gap e.g. between the obstacle body and the surrounding housing of the flow chamber forms the gap.
Through locating multiple obstacle bodies behind each other, due to space constraints, preferably shaped as discs perpendicular to the flow direction, the cavitation effect is multiplied, in particular, through reducing the annular gap surface in flow direction from one disc to the next.
In addition to the first cavitation field forming in the annular gap area, supplemental cavitation fields are created in the flow-through cavities between the obstacle bodies, and through spatial superposition of the particular cavitation fields a so called super cavitation field is created, causing a multiplication of the cavitation effect of each single cavitation field.
Thereby, it is state of the art to provide the reduction of the area of the annular gap in flow direction through:                a sequence of discs as obstacle bodies, increasing in size in flow direction, forming a cut off cone in their entirety in a surrounding cylindrical housing as flow through chamber, e.g. according to DE 44 33 744, or        in an also conical housing as flow through chamber, however with less conicity than the conicity of the cone or cut off cone formed by the obstacles, so that a reduction of the annular gap in flow through direction is still present, e.g. according to EP 1 280 598, wherein a so called hydrodynamic super cavitation field is created.        
It is, for example, state of the art to use the cavitation effect created in this manner for mixing a suspension or emulsion with minor effort and without mechanically driven parts.
When the collapse of a large number of bubbles, so called cavitation bubbles occurs in proximity to the separation surface between two phase areas, e.g. large oil droplets in water, thereby the second component, in this case the oil droplets are divided into smaller units and, thereby, a very fine mixture of the two components and a very fine suspension or emulsion are created.